$ git clone -n https://src.fedoraproject.org/rpms/openchange.git /var/lib/mock/f42-build-3279782-41338/root/chroot_tmpdir/scmroot/openchange
Cloning into '/var/lib/mock/f42-build-3279782-41338/root/chroot_tmpdir/scmroot/openchange'...
$ git fetch origin f06c50b85fdfc2630257f8884e8465d1b1d2641c:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/openchange
 * [new ref]         f06c50b85fdfc2630257f8884e8465d1b1d2641c -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at f06c50b Define SOURCE4_LIBRPC_INTERNALS to not need to change the code